两种生物质炭对酸性紫色土腐殖质组成的影响

赵海岚; 李冰; 王昌全; 龙思帆; 李斌; 鲜顺志; 曾林浩; 肖美娟; 刘奇鑫

doi:10.13930/j.cnki.cjea.200277

摘要: 生物质炭的性状与原料中木质纤维含量密切相关，为探明不同原料生物质炭对土壤腐殖质组成的影响，选取玉米秸秆和紫茎泽兰分别作为纤维类和木质类原材料制备生物质炭，向酸性紫色土分别添加5%玉米秸秆生物质炭（MB）和5%紫茎泽兰生物质炭（EB），测定90 d室内培养期间土壤胡敏酸（HA）、富里酸（FA）、胡敏素（HM）含量以及HA光学性质和元素组成变化。结果表明：MB和EB的比表面积分别为2.32 m²·g^-1和0.72 m²·g^-1，总孔体积分别为42.71 mm³·g^-1和12.59 mm³·g^-1，碳与氢元素摩尔比（C/H）分别为1.91和1.46，氧、硫之和与碳元素摩尔比（O+S）/C分别为0.09和0.16，玉米秸秆生物质炭的吸附能力更强、有机质成分的缩合度更大且氧化度更小。与对照（不添加生物质炭，CK）相比，培养结束后，施入生物质炭的土壤HA、FA和HM含量分别显著增加（P < 0.05）65.59%~102.82%、85.87%~118.54%和137.25%~161.23%，MB处理对这3种腐殖质含量的增加效应较EB处理更明显。培养结束时添加生物质炭的土壤HA/土壤有机碳（SOC）降低13.53%~27.06%，FA/SOC降低6.81%~18.03%，其中EB处理的降低效应达显著水平；HM/SOC则增加4.58%~11.40%，其中MB处理的增加效应达显著水平。添加生物质炭的土壤HA色调系数（ΔlgK）增加2.40%~5.60%，HA的缩合度（C/H）降低3.51%~11.81%，（O+S）/C增加1.51%~8.74%。总体来看，施入生物质炭均能相对增加腐殖质各组分含量，降低C/H，提高HA的氧化度（O+S）/C，且纤维类原料（玉米秸秆）生物质炭的效果更明显。纤维类原料（玉米秸秆）生物质炭显著提高了稳定性较高的土壤胡敏素碳比例（HM/SOC），但降低了土壤HA的稳定性HA的C/H降低，（O+S）/C增加；木质类原料（紫茎泽兰）生物质炭显著降低土壤胡敏酸碳比例（HA/SOC）和富里酸碳比例（FA/SOC），对HM/SOC增加效益不显著，反之提高了土壤易分解有机碳比例。

Abstract: Biochar characteristics are similar to feedstock lignin and cellulose contents. Two kinds of biochar were produced from cellulosic (maize straw) and ligneous (Eupatorium adenophorum) feedstocks, respectively, to evaluate how lignocellulosic feedstock biochar influence the humus composition in acidic purplish soil. Acidic purplish soil was treated with 5% maize straw biochar (MB) or 5% E. adenophorum biochar (EB) for 90 days, and the humic acid (HA), fulvic acid (FA), and humin (HM) contents, chemical elements, and HA color tonal coefficient were analyzed. The biochar specific surface areas were 2.32 m²·g^-1 (MB) and 0.72 m²·g^-1 (EB), and the total pore volumes were 42.71 mm³·g^-1(MB) and 12.59 mm³×g^-1 (EB). The carbon to hydrogen molar ratios (C/H) were 1.91 (MB) and 1.46 (EB), and the oxygen and sulfur to carbon molar ratios(O+S)/C were 0.09 (MB) and 0.16 (EB), indicating that the MB had a stronger adsorption capacity, a higher organic matter, condensation degree, and a lower oxidation degree. Biochar application significantly increased the soil HA, FA, and HM contents (P < 0.05) compared to no application (CK). After 90 days, biochar amendment increased the HA content by 65.59%-102.82%, increased the FA content by 85.87%-118.54%, and increased the HM content by 137.25%-161.23%. The MB increased the humus composition contents more than EB, and both treatments reduced the soil HA/soil organic carbon (SOC) values by 13.53%-27.06% and the FA/SOC values by 6.81%-18.03% (EB treatment P < 0.05). Both treatments also increased the HM/SOC values by 4.58%-11.40% (MB treatment P < 0.05). Biochar amendment increased the HA color tonal coefficient (ΔlgK) degree by 2.40%-5.60%, reduced the C/H of HA by 3.51%-11.81%, and increased the (O+S)/C by 1.51%-8.74%. The biochar application increased the content of each humic component, reduced the C/H condensation degree, and improved the HA oxidation degree; the effect was more prominent when MB was applied. MB application significantly increased the proportion and stability of HM/SOC, but reduced the stability of HAC/H decreased, (O+S)/C increased. EB biochar significantly reduced the proportion of HA/SOC and FA/SOC, and had no effect on the proportion of HM/SOC, and increased the proportion of labile organic carbon.

两种生物质炭对酸性紫色土腐殖质组成的影响

The effects of biochars on humus composition in acidic purplish soil